[mirror_ubuntu-artful-kernel.git] / fs / btrfs / delayed-ref.h

/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */
#ifndef __DELAYED_REF__
#define __DELAYED_REF__

/* these are the possible values of struct btrfs_delayed_ref->action */
#define BTRFS_ADD_DELAYED_REF    1 /* add one backref to the tree */
#define BTRFS_DROP_DELAYED_REF   2 /* delete one backref from the tree */
#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */

struct btrfs_delayed_ref_node {
	struct rb_node rb_node;

	/* the starting bytenr of the extent */
	u64 bytenr;

	/* the size of the extent */
	u64 num_bytes;

	/* ref count on this data structure */
	atomic_t refs;

	/*
	 * how many refs is this entry adding or deleting.  For
	 * head refs, this may be a negative number because it is keeping
	 * track of the total mods done to the reference count.
	 * For individual refs, this will always be a positive number
	 *
	 * It may be more than one, since it is possible for a single
	 * parent to have more than one ref on an extent
	 */
	int ref_mod;

	unsigned int action:8;
	unsigned int type:8;
	/* is this node still in the rbtree? */
	unsigned int is_head:1;
	unsigned int in_tree:1;
};

struct btrfs_delayed_extent_op {
	struct btrfs_disk_key key;
	u64 flags_to_set;
	unsigned int update_key:1;
	unsigned int update_flags:1;
	unsigned int is_data:1;
};

/*
 * the head refs are used to hold a lock on a given extent, which allows us
 * to make sure that only one process is running the delayed refs
 * at a time for a single extent.  They also store the sum of all the
 * reference count modifications we've queued up.
 */
struct btrfs_delayed_ref_head {
	struct btrfs_delayed_ref_node node;

	/*
	 * the mutex is held while running the refs, and it is also
	 * held when checking the sum of reference modifications.
	 */
	struct mutex mutex;

	struct list_head cluster;

	struct btrfs_delayed_extent_op *extent_op;
	/*
	 * when a new extent is allocated, it is just reserved in memory
	 * The actual extent isn't inserted into the extent allocation tree
	 * until the delayed ref is processed.  must_insert_reserved is
	 * used to flag a delayed ref so the accounting can be updated
	 * when a full insert is done.
	 *
	 * It is possible the extent will be freed before it is ever
	 * inserted into the extent allocation tree.  In this case
	 * we need to update the in ram accounting to properly reflect
	 * the free has happened.
	 */
	unsigned int must_insert_reserved:1;
	unsigned int is_data:1;
};

struct btrfs_delayed_tree_ref {
	struct btrfs_delayed_ref_node node;
	u64 root;
	u64 parent;
	int level;
};

struct btrfs_delayed_data_ref {
	struct btrfs_delayed_ref_node node;
	u64 root;
	u64 parent;
	u64 objectid;
	u64 offset;
};

struct btrfs_delayed_ref_root {
	struct rb_root root;

	/* this spin lock protects the rbtree and the entries inside */
	spinlock_t lock;

	/* how many delayed ref updates we've queued, used by the
	 * throttling code
	 */
	unsigned long num_entries;

	/* total number of head nodes in tree */
	unsigned long num_heads;

	/* total number of head nodes ready for processing */
	unsigned long num_heads_ready;

	/*
	 * set when the tree is flushing before a transaction commit,
	 * used by the throttling code to decide if new updates need
	 * to be run right away
	 */
	int flushing;

	u64 run_delayed_start;
};

static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{
	WARN_ON(atomic_read(&ref->refs) == 0);
	if (atomic_dec_and_test(&ref->refs)) {
		WARN_ON(ref->in_tree);
		kfree(ref);
	}
}

int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
			       struct btrfs_trans_handle *trans,
			       u64 bytenr, u64 num_bytes, u64 parent,
			       u64 ref_root, int level, int action,
			       struct btrfs_delayed_extent_op *extent_op,
			       int for_cow);
int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
			       struct btrfs_trans_handle *trans,
			       u64 bytenr, u64 num_bytes,
			       u64 parent, u64 ref_root,
			       u64 owner, u64 offset, int action,
			       struct btrfs_delayed_extent_op *extent_op,
			       int for_cow);
int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
				struct btrfs_trans_handle *trans,
				u64 bytenr, u64 num_bytes,
				struct btrfs_delayed_extent_op *extent_op);

struct btrfs_delayed_ref_head *
btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
			   struct btrfs_delayed_ref_head *head);
int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
			   struct list_head *cluster, u64 search_start);
/*
 * a node might live in a head or a regular ref, this lets you
 * test for the proper type to use.
 */
static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
{
	return node->is_head;
}

/*
 * helper functions to cast a node into its container
 */
static inline struct btrfs_delayed_tree_ref *
btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_tree_ref, node);
}

static inline struct btrfs_delayed_data_ref *
btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_data_ref, node);
}

static inline struct btrfs_delayed_ref_head *
btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(!btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_ref_head, node);
}
#endif
Commit	Line	Data
56bec294 CM	1	/*
	2	* Copyright (C) 2008 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18	#ifndef __DELAYED_REF__
	19	#define __DELAYED_REF__
	20
	21	/* these are the possible values of struct btrfs_delayed_ref->action */
	22	#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
	23	#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
	24	#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
1a81af4d	25	#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
56bec294 CM	26
	27	struct btrfs_delayed_ref_node {
	28	struct rb_node rb_node;
	29
	30	/* the starting bytenr of the extent */
	31	u64 bytenr;
	32
56bec294 CM	33	/* the size of the extent */
	34	u64 num_bytes;
	35
	36	/* ref count on this data structure */
	37	atomic_t refs;
	38
	39	/*
	40	* how many refs is this entry adding or deleting. For
	41	* head refs, this may be a negative number because it is keeping
	42	* track of the total mods done to the reference count.
	43	* For individual refs, this will always be a positive number
	44	*
	45	* It may be more than one, since it is possible for a single
	46	* parent to have more than one ref on an extent
	47	*/
	48	int ref_mod;
	49
5d4f98a2 YZ	50	unsigned int action:8;
5d4f98a2 YZ	51	unsigned int type:8;
56bec294	52	/* is this node still in the rbtree? */
5d4f98a2	53	unsigned int is_head:1;
56bec294 CM	54	unsigned int in_tree:1;
	55	};
	56
5d4f98a2 YZ	57	struct btrfs_delayed_extent_op {
	58	struct btrfs_disk_key key;
	59	u64 flags_to_set;
	60	unsigned int update_key:1;
	61	unsigned int update_flags:1;
	62	unsigned int is_data:1;
	63	};
	64
56bec294 CM	65	/*
	66	* the head refs are used to hold a lock on a given extent, which allows us
	67	* to make sure that only one process is running the delayed refs
	68	* at a time for a single extent. They also store the sum of all the
	69	* reference count modifications we've queued up.
	70	*/
	71	struct btrfs_delayed_ref_head {
	72	struct btrfs_delayed_ref_node node;
	73
	74	/*
	75	* the mutex is held while running the refs, and it is also
	76	* held when checking the sum of reference modifications.
	77	*/
	78	struct mutex mutex;
	79
c3e69d58 CM	80	struct list_head cluster;
c3e69d58 CM	81
5d4f98a2	82	struct btrfs_delayed_extent_op *extent_op;
56bec294 CM	83	/*
	84	* when a new extent is allocated, it is just reserved in memory
	85	* The actual extent isn't inserted into the extent allocation tree
	86	* until the delayed ref is processed. must_insert_reserved is
	87	* used to flag a delayed ref so the accounting can be updated
	88	* when a full insert is done.
	89	*
	90	* It is possible the extent will be freed before it is ever
	91	* inserted into the extent allocation tree. In this case
	92	* we need to update the in ram accounting to properly reflect
	93	* the free has happened.
	94	*/
	95	unsigned int must_insert_reserved:1;
5d4f98a2	96	unsigned int is_data:1;
56bec294 CM	97	};
56bec294 CM	98
5d4f98a2	99	struct btrfs_delayed_tree_ref {
56bec294	100	struct btrfs_delayed_ref_node node;
eebe063b AJ	101	u64 root;
eebe063b AJ	102	u64 parent;
5d4f98a2 YZ	103	int level;
5d4f98a2 YZ	104	};
56bec294	105
5d4f98a2 YZ	106	struct btrfs_delayed_data_ref {
5d4f98a2 YZ	107	struct btrfs_delayed_ref_node node;
eebe063b AJ	108	u64 root;
eebe063b AJ	109	u64 parent;
5d4f98a2 YZ	110	u64 objectid;
5d4f98a2 YZ	111	u64 offset;
56bec294 CM	112	};
	113
	114	struct btrfs_delayed_ref_root {
	115	struct rb_root root;
	116
	117	/* this spin lock protects the rbtree and the entries inside */
	118	spinlock_t lock;
	119
	120	/* how many delayed ref updates we've queued, used by the
	121	* throttling code
	122	*/
	123	unsigned long num_entries;
	124
c3e69d58 CM	125	/* total number of head nodes in tree */
	126	unsigned long num_heads;
	127
	128	/* total number of head nodes ready for processing */
	129	unsigned long num_heads_ready;
	130
56bec294 CM	131	/*
	132	* set when the tree is flushing before a transaction commit,
	133	* used by the throttling code to decide if new updates need
	134	* to be run right away
	135	*/
	136	int flushing;
c3e69d58 CM	137
c3e69d58 CM	138	u64 run_delayed_start;
56bec294 CM	139	};
	140
	141	static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
	142	{
	143	WARN_ON(atomic_read(&ref->refs) == 0);
	144	if (atomic_dec_and_test(&ref->refs)) {
	145	WARN_ON(ref->in_tree);
	146	kfree(ref);
	147	}
	148	}
	149
66d7e7f0 AJ	150	int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	151	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	152	u64 bytenr, u64 num_bytes, u64 parent,
5d4f98a2 YZ	153	u64 ref_root, int level, int action,
66d7e7f0 AJ	154	struct btrfs_delayed_extent_op *extent_op,
	155	int for_cow);
	156	int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
	157	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	158	u64 bytenr, u64 num_bytes,
	159	u64 parent, u64 ref_root,
	160	u64 owner, u64 offset, int action,
66d7e7f0 AJ	161	struct btrfs_delayed_extent_op *extent_op,
	162	int for_cow);
	163	int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
	164	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	165	u64 bytenr, u64 num_bytes,
5d4f98a2 YZ	166	struct btrfs_delayed_extent_op *extent_op);
56bec294	167
1887be66 CM	168	struct btrfs_delayed_ref_head *
1887be66 CM	169	btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
c3e69d58 CM	170	int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
	171	struct btrfs_delayed_ref_head *head);
	172	int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
	173	struct list_head *cluster, u64 search_start);
56bec294 CM	174	/*
	175	* a node might live in a head or a regular ref, this lets you
	176	* test for the proper type to use.
	177	*/
	178	static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
	179	{
5d4f98a2	180	return node->is_head;
56bec294 CM	181	}
	182
	183	/*
	184	* helper functions to cast a node into its container
	185	*/
5d4f98a2 YZ	186	static inline struct btrfs_delayed_tree_ref *
5d4f98a2 YZ	187	btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
56bec294 CM	188	{
56bec294 CM	189	WARN_ON(btrfs_delayed_ref_is_head(node));
5d4f98a2 YZ	190	return container_of(node, struct btrfs_delayed_tree_ref, node);
5d4f98a2 YZ	191	}
56bec294	192
5d4f98a2 YZ	193	static inline struct btrfs_delayed_data_ref *
	194	btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
	195	{
	196	WARN_ON(btrfs_delayed_ref_is_head(node));
	197	return container_of(node, struct btrfs_delayed_data_ref, node);
56bec294 CM	198	}
	199
	200	static inline struct btrfs_delayed_ref_head *
	201	btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
	202	{
	203	WARN_ON(!btrfs_delayed_ref_is_head(node));
	204	return container_of(node, struct btrfs_delayed_ref_head, node);
56bec294 CM	205	}
56bec294 CM	206	#endif